Tension device for a textile machine

ABSTRACT

A tensioning device for controlling the unwinding of plastic tape from a package comprising a pair of similar spring arms mounted side-by-side in cantilevered fashion at a spacing appreciably less than their lengths, the arms converging from their mountings into pressure contact with one another to define a nip through which the tape may pass.

United States Patent Inventor John K. P. Mackie Bellast, Ireland Appl. No. 791,386 Filed Jan. 15, 1969 Patented July 27, 1971 Assignee James Mackie 8: Sons Limited 7 Ireland Priority Jan. 23, 1968 Great Britain 3541/68 TENSION DEVICE FOR A TEXTILE MACHINE 6 Claims, 2 Drawing Figs.

Int. Cl. B65h 59/22 Field of Search 242/ I49, 147. 75.2

[56] References Cited UNITED STATES PATENTS 657,351 9/1900 Miller 242/ I 49 2,223,912 12/1940 Guenther 242/149 X Primary Examiner-Stanley N I Gilreath Auomey- Larson, Taylor & Hinds ABSTRACT: A tensioning device for controlling the unwinding of plastic tape from a package comprising a pair of similar spring arms mounted side-by-side in cantilevered fashion at a spacing appreciably less than their lengths, the arms converging from their mountings into pressure contact with one another to define a nip through which the tape may pass.

TENSION DEVICE FOR A TEXTILE MACHINE When yarn is being withdrawn from a package on a creel it is generally necessary to fit a tensioning device adjacent the package so that yarn from that point onwardly can be maintained under sufficient tension to prevent undue sagging. This is particularly important in a creel for a beaming machine where there are generally a very large number of separate yarns and the sagging of a singly yarn into contact with that adjacent it will cause the whole machine to be stopped. In some cases instead of withdrawing yarns from the creel it may be necessary to withdraw narrow plastic tapes and if these are withdrawn overend from the packages an additional complication is introduced since each tape will include a turn of twist for each turn round the package and these turns of twist must pass through the tensioning devices.

The problem is slightly more acute if the tapes have been wound on the packages in accordance with the method described in the copending application Ser. No. 665,615 filed Sept. 5, 1967, in which periodic folds are inserted in the tape during the winding process. These folds are made in the reverse direction to the twist inserted during unwinding and since there is one fold for each turn around the package these folds effectively cancel out the twist which is introduced so as to yield an untwisted tape. This means that both the folds in one direction and the turns of twist in the opposite direction must pass through the tensioning devices, following which the tension in each tape causes the folds to be removed so as to cancel out the turns oftwist as just described.

This requirement for the tensioning devices to pass turns, and also in the latter case just mentioned folds, in the tape renders the normal type of spring loaded device unsuitable. Generally speaking these devices are adjustable in order to provide corresponding adjustment of the tension in the yarn or tape. If adjusted too tightly, the device then completely prevents the passage of the twist which thus accumulates behind the device until a breakage occurs. On the other hand if the devices are slackened off sufficiently to permit the passage of the twist, and also the folds if required, the action is sluggish and after the passage of a turn of twist or a fold through the device, the device does not immediately regrip the tape and a momentary slackness is introduced into the tape which may lead to entanglement with adjacent tapes. There are thus two opposing requirements for the tensioning devices, namely, that they should allow the turns of twist and folds (if any) in the tape to pass relatively freely but at the same time they should not allow the formation of momentary slack just mentioned. It is found to be impossible to adjust the normal form ofdevice to satisfy both these requirements.

According to the present invention a tensioning device for controlling the unwinding of plastic tape from a package comprises a pair of similar spring arms mounted side by side in cantilevered fashion at a spacing appreciably less than their lengths, the arms converging from their fixed portions into pressure contact with one another to define a nip through which the tape may pass. The converging space between the arms guides the tape to the nip which exerts a degree of tension control such as to satisfy the requirements mentioned In order to lead the tape into the converging space and thence to the nip a guide opening may conveniently be formed in one of the arms at or close to its mounting. In practice both arms need to be made considerably wider than the tape so as to allow for lateral wander of the tape without the need for any other form of controlling guide which might otherwise increase the tension and lead to the formation of snarls. The tendency to lateral wander arises from the fact that when the tape unwinds from the package it is in a series of loops and the straightening of these loops inevitably diverts the tape from its straight line path.

A construction in accordance with the invention will now be described in more detail by way of example with reference to the accompanying drawings in which:

FIG. 1 is a perspective view showing the device mounted on an upright support of the creel adjacent the end of a package supported by the creel; and

FIG. 2 is a plan view of the device.

The device itself is indicated generally as 1 and is shown mounted on an upright support 2 forming part ofa creel. If the creel is fora beaming machine, for example, there may be a thousand or more of the devices mounted one above the other on spaced uprights and the top of the next lower device is shown in dotted lines as 1'. The device 1 is intended to apply tension control to a tape 4 of synthetic plastic material which is being withdrawn over the end of a package indicated generally as 5. As illustrated the tape has been wound in accordance with the method described in the application referred to above, as a result of which it has folds 8 at regular intervalsalong its length. The overend withdrawal from the package 5 inserts turns of twist to the tape in the opposite direction to the folds 8, one of these turns being shown, for example at 9. The tape 4 with its folds 8 and twists 9 passes through the device, following which the tension on the tape removes the folds so as to cancel the turns of twist and leave a flat untwisted tape as shown at 12, which will nevertheless bear slight fold marks shown as 13 at the point where the folds previously existed.

The device 1 comprises a pair of similar spring arms 16 and 17 mounted respectively on the upright support 2 of the creel and on a bracket 19 which is pivoted to a flange 20 on the side of the upright 2. The spring arms 16 and 17 are made from a above. Thus although the pressure between the arms may be made light enough to allow the passage of twist and folds the response is nevertheless so rapid that immediately after the passage of such twists or folds the grip on the tape is immediately resumed before the formation of any appreciable standard grade of spring shim steel and their inner surfaces are extremely smooth so as to avoid the application of any additional drag to the tape. As best seen from FIG. 2 the spring arms 16 and 17 converge from their mountings so as to define a converging space 22 which guides the tape 8 to a nip 23 formed between a short length of the free ends of the arms.

A guide eye 25 extends through the upright 2 and through the spring arm 16, being held in position by a nut 26 which thus also serves to clamp the arm 16 firmly in position. The arm 17 is riveted to its bracket 19 which is adjustably pivoted to the flange 20 by the provision of fingers 27, 28 and 29 which'as best seen from FIG. 2 fit alternately on opposite sides of the flange 20. This arrangement permits pivoting both about an axis along the edge of the flange 20, i.e. parallel with the width of the arms and about an axis at right angles to this, i.e. parallel with the length of the arms. The latter pivoting movement occurs about central finger 28. The former pivoting permits adjustment of the pressure between the pressure between the arms and the latter pivoting ensures that the width of "the nip between the arms and hence the pressure between them is uniform. The bracket 19 is located in relation to the upright 2 by a bolt 30 fitted with an adjustable finger nut 31. By tightening the nut 31 the bracket 19 is pivoted about the edge of flange 20 towards the upright 2 and the pressure infore the formation of any slack. As can be seen the width of .the arms 16 and 17 is considerably greater than that of the tape 4 so as to allow for the possibility of lateral wander as previously described.

As can be seen the device as a whole is extremely simple and can be manufactured very cheaply and fitted to existing creels. Although particularly useful for the controlling of plastic tape wound by the method of the earlier patent application referred to above it is also useful with plastic tape wound in a normal manner and for controlling of normal yarns in view ofits cheapness and rapid response.

lclaim:

1. A tensioning device for controlling the unwinding of plastic tape from a package, said device comprising a pair of similar spring arms, means mounting said arms side-by-sidc in cantilevered fashion at a spacing between said arms appreciably less than the lengths of said arms, the arms converging from said mounting means into pressure contact with one Y another to define a nip through which said tape may pass and means pivoting said mounting means whereby said arms may be pivoted relatively about about a first axis parallel with the width of said arms whereby to permit adjustment of the pressure between said arms'and also about a second axis parallel with the length of said arms whereby the pressure between said arms may be equalized along said nip.

2. A device according to claim 1, in which said arms are constituted by separate,- rigidly mounted leaf springs.

3. A device according to claim 1, in which said arms engage one another over a short length close to the free ends thereof' 4. A device according to claim 1, wherein one of said arms has a guide opening for said tape in the region of said mounting means.

5. A device according to claim 1, wherein the mounting means includes an adjustable screw for pressing together said mounting means.

6. A device according to claim 1, wherein the mounting means comprises a fixed support and a pivotable bracket, said fixed support having a flat edge and pivotable bracket having fingers fitting alternately on opposite sides of said flat edge, said fingers and flat edge constituting said means for pivoting said mounting means. 

1. A tensioning device for controlling the unwinding of plastic tape from a package, said device comprising a pair of similar spring arms, means mounting said arms side-by-side in cantilevered fashion at a spacing between said arms appreciably less than the lengths of said arms, the arms converging from said mounting means into pressure contact with one another to define a nip through which said tape may pass and means pivoting said mounting means whereby said arms may be pivoted relatively about about a first axis parallel with the width of said arms whereby to permit adjustment of the pressure between said arms and also about a second axis parallel with the length of said arms whereby the pressure between said arms may be equalized along said nip.
 2. A device according to claim 1, in which said arms are constituted by separate, rigidly mounted leaf springs.
 3. A device according to claim 1, in which said arms engage one another over a short length close to the free ends thereof.
 4. A device according to claim 1, wherein one of said arms has a guide opening for said tape in the region of said mounting means.
 5. A device according to claim 1, wherein the mounting means includes an adjustable screw for pressing together said mounting means.
 6. A device according to claim 1, wherein the mounting means comprises a fixed support and a pivotable bracket, said fixed support having a flat edge and pivotable bracket having fingers fitting alternately on opposite sides of said flat edge, said fingers and flat edge constituting said means for pivoting said mounting means. 